Cardiovascular risk in osteopenic postmenopausal women linked to ET-1

Abstract

MedWire News: The increased cardiovascular risk seen in postmenopausal women with osteopenia may be related to an increase in endothelin (ET)-1-mediated vasoconstrictor activity, show US study findings.

Osteopenia in postmenopausal women is an established predictor of adverse cardiovascular events, but few studies have looked at the mechanisms linking the two.

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Brian Stauffer (University of Colorado, Boulder) and colleagues say this is the first study to determine whether postmenopausal women with osteopenia have elevated ET-1-mediated vasoconstrictor tone. They add: "Our findings represent a potentially important link between osteopenia and increased cardiovascular risk."

For the study, the researchers measured forearm blood flow responses to intra-arterial infusion of a selective ETA receptor antagonist (BQ-123; 100 nmol/min for 60 minutes) in 10 postmenopausal women with osteopenia and 12 without osteopenia aged on average 56 and 60 years, respectively.

Women with osteopenia had lumbar spine T-scores between -1.5 and -2.5, while those without osteopenia had T-scores above -1.5. All women were at least 1 year postmenopausal and had either never taken hormone replacement therapy or discontinued its use at least 1 year prior to study commencement.

At baseline, blood flow did not differ significantly between women with and without osteopenia. Following infusion of BQ-123, women with osteopenia showed a significant vasodilator response, with forearm blood flow increased by approximately 25% from baseline. In the women without osteopenia, resting forearm blood flow was not altered in response to BQ-123 infusion.

Writing in the journal Bone, Stauffer et al conclude: "It is possible that increased ET-1 activity plays a mechanistic role in the development of osteopenia and osteoporosis. Future studies are necessary to establish an etiologic link between the ET-1 system and bone-density."